Okay, I have been planning this damn oven for some time now, the Spring is here and I am ready to start...
I would really love to have a nice big thermometer showing the dome temperature at a glance, kinda like the ones you get on a weber bbq (but BIGGER).
Where on earth can I find something like this in the UK. Has anyone else done this I have searched the forum but not found anything.

I will take some photos soon so you can all follow the build.

Also if there is anyone in East Sussex Kent area that needs to buy fire bricks, we could chip in together to get the price right down.

Most barbecue thermometers only go up to 600 F. These can be useful mounted in the door for slow cooking. For measuring the higher temperatures most go with a hand held infrared thermometer, or a thermocouple system.

How did you make your thermocouple? I've got the appropriate 22ga wire with SS braid jacket. Do you just twist the ends together or what?? And, which wire is the (+) positive — the one with the stripe or plain? When I plug the bare wires into my meter with the stripe in the (+) side I get a reading that is approximately what I have on a thermometer sitting on my desk. With the stripe wire in the (-) side it seems like the temp reads 4-5 degrees less. I guess the stripe wire is (+) positive?

James has a nice thermometer for sale with a big dial and 3m cable for the remote probe. It is a little pricey at $200, but is a nice piece. I have mine mounted inside the oven 4" above the floor. The thing about temperatures is that it is different depending on where you are measuring it. When my thermometer reads 700, the dome is 800- 1000 depending on how vigorous the fire is. So for cooking you need to get a feel for the oven, depending on how long it has been fired, how big your current fire is etc.
The thermometer mounted in the oven does give me a reference, then I use the IR for measuring the floor temp. I have linked some photos of my install
Good Luck,
Eric

My build is using a dual thermocouple (one floor, one dome) and dual pyrometer system. The instruments are Diesel pyrometers from VDO, and they are backlit and sexy. Basically they are the instruments you might find in a Mercedes-powered boat, and are simple to read and range from about 200 to 1650 degrees, and one should be able to distinguinsh 50 degree increments. Summit Racing has them. You will need to get a transformer to step down household voltage to 12VDC.

How did you make your thermocouple? I've got the appropriate 22ga wire with SS braid jacket. Do you just twist the ends together or what?? And, which wire is the (+) positive — the one with the stripe or plain? When I plug the bare wires into my meter with the stripe in the (+) side I get a reading that is approximately what I have on a thermometer sitting on my desk. With the stripe wire in the (-) side it seems like the temp reads 4-5 degrees less. I guess the stripe wire is (+) positive?

I used a resistance spot welder to fuse my thermocouple wire together just because I had easy access to one. My second choice would have been silver solder. I think the melting point of silver solder is sufficient for temperatures reached in a WFO but I would double check before you use it. As for which wire is + and which is -, a magnet will stick to the negative wire and not to the positive.

Each pyrometer comes with a little Inconel shielded thermocouple with a braided leader, which you can then set into desired locations. They are threaded, as they are really meant to screw in really hot Diesel exhaust systems, but I just took the washer off and set them in strategic holes in the cupola.

Also I figure the sensing tip of the thermocouple should go be placed as far to the exterior wall of the thermal mass as possible, and beneath the insulation. That way the temperature readings are more likely to represent the "true" temp of the dome rather than the temperature of the air/ combustion gas inside the cupola. When an external pyrometer reaches 700F, then you know the brick mass beneath it is at least that hot.

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